Most security bars, such as those used in prisons, stores' or banks' barred windows, and auto theft devices such as, for example, the Club® (a registered trademark of Winner International Royalty LLC), are one solid bar made of an appropriately strong metal such as iron. Most typically, the biggest threat to the breach of security of a security bar is a hacksaw or similar tool, which is used to cut completely through the security bar, thereby rendering it useless.
One approach that has been suggested is to insert a free rolling internal metal bar inside an outer metal bar which has been fabricated in the form of a hollowed out cylinder. Thus, using a hacksaw, for example, to saw through one side of the bar will be fruitless—once the hacksaw encounters the free rolling inner bar, the inner bar will simply roll back and forth along with the movement of the hacksaw, and will therefore not be cut at all.
However, a security bar fabricated with the above described approach can nonetheless be breached by using two hacksaws in concert. In particular, the two hacksaws may be used to cut simultaneously on opposite sides of the security bar, sawing in the same direction with equal pressure. In this manner, once the outer bar has been cut through and the inner bar reached, the inner bar will not be able to roll, but rather, will also be cut by the two hacksaws working together.
Therefore, it would be highly desirable to provide a security bar which cannot be breached, even with the use of multiple hacksaws. In addition, it would be highly desirable to provide such a security bar whose breach or attempted breach can be monitored automatically (e.g., electronically).